The present invention relates generally to utility loops, and more particularly, to a sling with a braided sleeve covering and a method for making the same.
A utility loop generally consists of a loop core and an outer covering. Utility loops may be used for a variety of purposes, including restraining cargo. Several utility loops may be linked together using chains, for example, to form greater lengths.
The loop core is usually formed of a strong fibrous core material. The loop core may be braided of multiple strands of fiber into a long, linear form. The braided loop core is then cut to a desired length, and the two ends are manually spliced together by interweaving the loose ends of the braided loop core. A utility loop may also be formed from a single strand of fibers by making multiple wraps around two or more pins. The two ends of the single strand can then be tied together to form a loop or, alternatively, can be left untied in which case friction serves to keep the loop together. Since the braided method of forming the loop core is manual, this method is relatively slow and expensive. The resulting splice from this method leaves an undesirable lump in the loop core, as well.
Additionally, a braided loop core is structurally inferior, since the angle of the braided fiber allows the loop core to change in length. Thus, extra tension must be applied to the braided loop core to remove slack and, further, the resulting braided loop core is not as rigid as might be desired.
The outer covering of the utility loop serves a function of protecting the loop core. In particular, the outer loop covering protects the loop core from abrasion, cuts, and ultraviolet degradation. The outer loop covering may take at least three forms. Specifically, the outer loop covering may be braided, woven, or molded. Molded outer loop covers, which are sufficiently abrasion and cut resistant, tend to be unacceptably stiff. Woven outer loop covers tend to be baggy and wrinkly, producing spots of high wear at the top of each wrinkle, for example.
U.S. Pat. No. 4,843,807, and German Patent No. 2,716,056, both disclose a woven outer loop cover. The woven outer loop cover is compressed in length over a semi-circular support by crumpling (bagging up) the outer loop cover. No significant increase in the diameter of the outer loop cover occurs as the outer loop cover is compressed in length and placed over the semi-circular support. The loop core is then formed within the compressed outer loop cover.
When the woven outer loop cover is removed from the semi-circular support and spread out over the length of the newly-formed loop core, the diameter of the woven outer loop cover remains unchanged. The result of this fixed diameter of the woven outer loop cover is a baggy outer loop cover. Thus, the inside of the outer loop cover is substantially larger than the space necessary to accommodate the loop core. This bagginess of the woven outer loop cover can inhibit secure knots from being formed, by wrinkling and hanging up in the tightening-up process. Making taut connections between the load and the vehicle, for example, is an element crucial to safety in the application of many utility loops which may be compromised. Additionally, a baggy outer loop cover adds excessive weight and volume to the utility loop, which reduces the number of utility loops that can be carried by a person and increases storage space in the vehicle, for example.
A utility loop consisting of a multiple-strand loop core and a braided outer loop covering is needed which is both durable, and which provides expansion characteristics to allow for a snug, yet flexible, fit of the braided outer loop cover over the multi-wrap loop core. Although the prior art has endeavored to braid an outer loop cover over an endless-loop core using a braiding machine, the engineering of the material and structure of the braided outer loop cover has been insufficient, and further, this braiding-in-place method of the prior art has been expensive because of the set-up time required to start and end each braid.